What does Vario-Tessar in Sony camera mean?

Carl zeiss's profound attainments and strict quality management system in the field of optical lens production have created top-quality lenses recognized worldwide. "Vario-Tessar" lens, with its high resolution, high contrast and nuanced color expression, makes the captured image perfectly reproduced, which is the guarantee of top image quality. Vario-Tessar is a zoom lens derived from Tessar.

Tessar: Designed for standard wide-angle lens, it is mainly composed of four lenses and three groups of lenses, featuring small deformation and light weight. Tessar comes from Greek tessares with patent number 1902, which was invented by Dr. paul rudolph, an optical designer of Zeiss. At first, it was only f/6.3. 1930, Zeiss optical designer Ernst Wanders Leib and Willy Merté made Tessar lenses with f/3.5 and f/2.8 using optical glass containing rare earth element "La".